Winding mandrel with suction means



Jan. 29, 1957 e. R. ROBERTS ET AL 2,779,547

WINDING MANDREL. WITH SUCTION MEANS Filed July 6, 1954 United States Patent @iiice 2,779,547 Patented Jan. 29, 1957 Development and Research Limited, London, England, a company of Great Britain Application July 6, 1954, Serial No. 441,452

Claims priority, application Great Britain July 14, 1953 Claims. (Cl. 242-74) This invention comprises improvements in and relating to winding mandrels equipped with suction means for anchoring the leading portion of the material to be wound.

Winding mandrels are known which have a longitudinal groove in the mandrel surface connected through apertures to a suction box, the leading end of the web to be wound, placed over the groove, being thus held on the mandrel by suction. This is satisfactory when the material to be wound is light but is unsatisfactory for thicker and heavier types of paper, such as kraft and chipboard used in the manufacture of convolute paper drums.

The object of the present invention is to provide a winding mandrel having improved suction means which will satisfactorily anchor thick and heavy webs even when wound under considerable tension.

According to the invention a winding mandrel having a longitudinal suction box in its surface for anchoring the leading end of a web to be wound is characterised by an apertured pad of resiliently deformable material such as rubber or the like fitting into the suction box.

The outer surface of the pad is preferably formed with a radius of curvature less than that of the mandrel and normally stands proud of the mandrel surface, but so that under pressure of the web as it is wound on the mandrel the pad will be compressed so that its outer surface conforms with the remainder of the mandrel surface.

The apertures in the pad may be formed in the bottoms of longitudinal grooves in the outer surface of the pad, and the inner surface of the pad may be recessed to provide a suction passage in the box and to leave side legs supported by the bottom of the box.

An embodiment of the invention as applied to a contractible winding mandrel such as is described in our copending application Serial No. 441,494, filed July 6, 1954, now abandoned, will now be described with reference to the accompanying drawings in which:

Figure 1 is a part transverse section through a winding mandrel according to the invention, and

Figure 2 is a plan view showing a modification in a detail of Figure 1.

Referring to Figure 1 a contractible winding mandrel comprises a drum mounted for rotation about the axis of a hollow shaft 1 and provided with a slot parallel to the axis of rotation of the shaft and running substantially the length of the drum and in which is positioned a suction box 2. A pipe 3 is joined at one of its ends to the centre of the suction box at 4, the other end being connected to an external vacuum pump through a rotary seal (not shown) at an end of the mandrel.

An apertured pad of non-porous rubber fitting into the suction box is indicated generally at 6. The pad 6 is formed so that its outer surface has a radius of curvature less than that of the drum and projects beyond or stands proud with respect to the surface of the drum. The pad may include a surface piece 7, the leading and trailing edges of which overlie the walls of the suction box 2 and are substantially flush with the adjacent surfaces of the drum. The pad and surface piece are apertured by holes 8 at spaced points along their lengths to form passages through the pad and surface piece. The inner surface of the pad is longitudinally recessed as at 9 to provide a suction passage communicating with the pipe 3 and to leave side supporting legs 10 and 11 standing on the bottom of the box 2. At the centre the inner surface of the pad is further recessed in a circle at 12 to clear the top of the joint of the pipe 3.

in operation the vacuum pump is started and the leading portion of the paper to be wound is smoothed over the outer surface 7 of the pad 6. The paper is drawn by suction at the holes 8 into frictional anchorage upon the pad. When the mandrel is set into rotation and the paper is tensioned during winding, the pad 6 becomes deformed and its outer surface 7 substantially conforms with the remainder of the mandrel surface. When the winding is finished the vacuum is released, the mandrel contracted, and the wound product may be withdrawn.

in Figure 2 is shown a slightly modified form of the pad 6 wherein grooves 13 and 14 run longitudinally of the outer surface *7, the holes 8 opening in these grooves. In operation the paper is drawn by suction at the grooves into frictional anchorage upon the pad.

Other features of a convolute winder in conjunction with which the present invention may be used are described in our co-pending applications Serial Nos. 441,494, now abandoned, 441,495, 441,496, and 441,497, filed July 6, 1954.

What is claimed is:

l. A rotatable sheet Winding mandrel comprising a substantially cylindrical drum having an outer convex surface interrupted by a slot extending substantially the length of said drum and parallel to the axis of rotation of the mandrel; a suction box positioned in said slot; an apertured pad of deformable material substantially coextensive in length with said slot fitted into said suction box and having an outer surface formed on a radius of curvature less than that of said drum and standing proud of the outer surface of the latter; and means for applying suction to said suction box, the apertures of said pad forming passages therethrough for enabling the application of suction to the leading end of sheet material on the outer surface of said mandrel.

2. A mandrel according to claim 1 wherein the outer surface of said pad is provided with grooves parallel to said slot, the apertures of said pad being located in said grooves.

3. A mandrel according to claim 1 wherein the inner surface of said pad has integral supporting legs at its sides and a recess between said legs, said recess providing a suction passage.

4. A sheet Winding mandrel comprising a substantially cylindrical drum having its outer surface interrupted by a slot; a suction box positioned in said slot; an apertured pad of deformable material substantially coextensive in length with said slot fitted into said suction box and normally having a portion of its outer surface projecting beyond the outer surface of said drum with the edges of said pad adjacent to the edges of said slots being sub stantially flush with the surface of said drum; and means for applying suction to said suction box, the apertures in said pad forming passages therethrough for enabling the application of suction to the leading end of sheet material to be wound on the mandrel, the deformability of said pad being such that when sheet material has been Wound around said mandrel said projecting portion of said pad substantially conforms with the outer surface of said drum.

5. A rotatable sheet winding mandrel comprising a substantially cylindrical drum having its outer surface interrupted by a slot extending substantially the length of said drum and parallel to the axis of rotation of the a) mandrel; a suction box posittened in said slot; an apertured pad of deformable materiat substantially coextensive in length with said slot fitted into said suction box and normally having a portion of'its outer surface projecting beyond the outer surface of said drum with the edges of said pad adjacent to the edges of said slot being substantially flush with the surface of said drum; and means for applying suction to said suction box, the apertures in said pad forming passages therethrough for enabling the application of suction to the leading end of 4 sheet material to be wound on the mandrel, the deformability of said pad being such that when sheet material has been wound around said mandrel said projecting portion of said pad substantially conforms with the outer surface of said drum.

M'acChesney June 12, 1 945 Christman. Feb. 12,, 1952 

